Centrifugal blasting machine



Nov. 1s, 1941. E UNGER 1 y 2,263,321

CENTRIFUGAL BLAS T ING .MACHINE Filed June 1, 1940 4 sheets-sheet 1 I lNvENToR ATTORNEY Nov. 18, 1941. A Q E UNGER 2,263,321

i CENTRIFUGAL BLASTING MACHINE Filed June l, 1940 4 Sheets-Sheet 2 ATTORNEY Nov. 18, 1941. c. E. UNGER CENTRIFUGAL BLASTING MACHINE 4 Sheets-Sheet 3 Filed June l, 1940 .QVENTOR (healer BY ATTORNEY m2 m51 E 5 Nov. 18.), 1941. c. E. UNG-ER CENTRIFUGAL 'BLASTING MACHINE 4 Sheets-Sheet 4 Filed June l, 1940 Patented Nov. 18, 1941 UNITE- o STAT-ss PATENT OFFICE CENTRlFUGAL BLASTIjNG MACHINE Chester E, Unger, Mishawaka,I Ind., assignor to rIhe American 'Foundry Equipment Company, Mishawaka, Ind., a corporation of Delaware Application June 1, 1940, Serial No. 338,294,

14 Claims.

This invention relates to ar centrifngal blasting machine, and more particularly to ay centrifugal blasting unit Wheh may be manipulated by the operator to bring the stream of abrasive fired thereby im@ @braiding ccntact with the surfaces` of the workpiece to be cleaned.

While centrifugal abrasive throwing wheels are generally known and in general use, such wheels have'generally been mounted on a pla-tform or support in such manner that the operator has no control over. the direction of the blast during operation. `With such units conveyors have been provided to carry the Work into the fan-shaped stream from the abrasive throwing wheel and the operator has been unable to shift at will the direction of thered stream of abrasive over the surfaces of the workpiece. vVihile ecpnomics in operation and speed of cleaning attained by centrifugal wheeis eyer the air blast sun are. generally lsnewn and reeesnned in the. ne dentrlfneal blasting unit has. heretofdfe. been Provided Willen @Ould be eenvenently manipulated by hand Se aS te dirent the fired allsV-e again@ any @Qsrefl Stimme@ Sulfate@ f @he WQTEP. 9? Q be. Qlldl Lame massive aff-ld irregular eaetinas and terelnns, havev therefore' been heetefere' eleaned by hand-Inaninnlated an. blast, anne en tiniest. ef this ini/enden le te provide a practical` centrifugal blasting unit designed `to permit convenienty movement and'manipulation thereofv over, under and aroundwthe surfaces of large or intricate' castings, forgings, bars or sheets which have heretofore been cleaned and treated by air blast guns.

Another object of this invention is to provide a portable centrifugal blasting unit which is suitably housed to protect the operator but which can be easily and conveniently manipulated by the operator over, under and around the workpiecef A d Another object of this invention isv to provide av portable centrifugal blasting unit which is admirably Fadapted for blast room use.

Still another object of this invention is to provide a centrifugal blasting unit which is sturdy and strong in construction, which reduires a minimum fhorsepower to operate, which is constructed to provide a minimum ofv power loss in transmission, and which has means for adjusting and shifting the directional control means associated with the centrifugal rotor during operation by an operator who may observe the progress of the blasting. operation at a safe distance from the abrasive blast.

Other objects of, this invention will become. apparent as the disclosure proceeds.

In accordance with thisinvention, a bladed centrifugal blasting wheel orrotor is xed directly to the shaft of a driving motor so as toV reduce power. transmission losses to a minimum. The abrasive throwing wheel is partially enclosed in a guard housing having an opening` through the abrasive red by the wheel may escape without impediment. A suitabler sling or, carriage extending around la framework xed tothe eX-v terior shell of the motor provides means by which the unit as a whole may be flexibly suspended from an overhead suspension device or supported by a suitable floor or wall pedestal or bracket. The, directional control device, such as the tulaular control cage positioned within the central part of the retor, is adjustably xed to the guard housing which partially encloses the wheel. A hand manipulatingmeans, such as a handwheel, ie denneeted te one, end 0f the meter Snppdrting' framework at a point removed from the abrasive throwing rtor. The guard housing for the wheel isconnected to the opposite end'of the motor Snfpnertina framework! The unit is Se een: Strneted that by' manipulating er turning thev hand vwheel, the framework, motorr shell, and gua d housing may 'be rotated'to any desired eleekdial nesitenvitlnn the Supporting Carriage 0r suspension .Ineens Se ae te dwing the' discharge Opening ,in tlle eiland nonnina inte any desired clockdial position to best direct' the red abrasive' against the workpiece under treatment. Such shifting movement of the discharge opening in thehosing will likewise shift Ythe control device which rattachedY to the guard housing so that the proper" desired discharging relationship betweenthe control device and the opening in the guard' housingy will be uniiormly maintained. Means are provided for initially adjusting the discharge port in the control device so as to place it in proper clockdial position with respect to vthedis'charge opening in the guard housing.

YBy the provision of supporting means for the unit, such as a suspension device, the whole unit may be swung around in a circle and over an area which is limited only by the nature of the supporting device, by the operator who exerts a slight pushing or pulling force on the hand wheel which also controls the direction of blast. Where an overhead suspension'means is used, a simple block and tackle suspension means may be provided, the upper end of whichis connected to a fixed frame or 'a movable frame or boom arm. Abrasive is fed to the rotor'from an overhead abrasive supply bin by a flexible abrasive supply conduit which does not interfere with the shifting movement of the unit. Suitable electrical control means, such as push buttom or other switch devices, may be conveniently located on or adjacent to the manipulating handle for controlling the operation of the driving motor. The hand wheel may be connected to the motor framework by means of a connecting neck or shank of any desired length so that the operator can position himself at a convenient, safe distance from the abrasive blast fired by the rotor. This connecting neck or shank may be made of tubular pipe within which the motor wires, circuits and switches may be protectively contained. The operator may station himself within the blasting room or outside of the blasting room, and in the latter case one wall of the blasting room is provided with suitable flexible curtains through which the neck portion of the unit may extend so that the hand wheel can be manipulated from a point entirely exterior to the blasting room. l

The centrifugal abrasive throwing rotor comprisingpart of this portable blasting unit, may be made in diameters of from s-ix inches to twenty inches or more, with a blade width varying from one-hall:` inch to three inches or more. The driving motor is driven at an R. P. M. of such a nature that abrasive fired by the rotor will impinge the workpieces at blastingvelocities. In other words, the motor should drive the rotor at a speed which will produce a linear velocity at the periphery of the blasting rotor of from yeight to twelve thousand linear feet per minute. For example, if the rotor is eight inches in diameter, a motor of from three to four thousand R. P. M. should be selected. While a variable speed motor may be employed, in the usual installation a constant speed motor will be used of sufficient R. P. M. to drive the attached abrasive throwing rotor at the desired peripheral speed.

An abrasive throwing Wheel of eight inches in diameter, for example, is capable of throwing from twenty to fifty pounds of abrasive per minute when driven by a one-horsepower motor. This compares with a blast gun throwing an equivalent amount of abrasive using compressed air requiring from fifteen to thirty horsepower to produce. nomies over the compressed air system are attained by this unit and, in addition, it can be manipulated as desired by the operator with a minimum of effort to uniformly blast and clean intricate castings and workpieces with the blasting operation under constant control and observation of the operator. A longfelt need for a practical, commercial, portable centrifugal blasting unit which has substantially all the flexible features of the air blast gun, with the accompanying advantages of faster and more thorough blast cleaning of intricate workpieces and substantial savings in operating costs, `is admirably supplied by the centrifugal blasting unit herein disclosed.

Various other features and advantages of the invention will be apparent from the following particular description and from an inspection of the accompanying drawings.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be carried out, may be better Substantial operating ecounderstood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which:

Fig. 1 is a perspective View of the portable centrifugal blasting unit shown swingably suspended from an overhead support and guided by an operator;

Fig. 2 is a front elevational View of the Wheel housing and a portion of the abrasive supply line;

Fig. 3 is an enlarged elevational view of the hand wheel used by the operator to manipulate the unit;

Fig. 4 is an enlarged longitudinal cross-sectional View through the unit as it appears when looking in the direction of the arrows 4 4 of Fig. l;

Fig. 5 is a cross-sectional view through the abrasive throwing wheel or rotor and its guard housing as it appears when looking in the direction of the arrows 5 5 of Fig. 4;

Fig. 6 is another cross-sectional view through the unit as it appears when looking in the direction of the arrows 6 6 of Fig. 4, certain parts being broken away to illustrate certain structural details;

Fig. '7 is a cross-sectional View through the tubular control cage which may be used to control the direction of blast from the wheel;

Fig. 8 is a perspective view of the impeller which is positioned within the tubular control cage and secured to rotate with the wheel; and

Fig. 9 is an enlarged view of the motor control switch positioned within the switch box at the center of the unit manipulating hand wheel. l

Similar reference characters refer to similar parts throughout the several views of the drawings and the specification.

Referring to the drawings, the centrifugal projector therein disclosed comprises generally a bladed abrasive throwing wheel or rotor r, which is xed to the shaft of a driving motor m. Y Abrasive in the desired quantities is supplied to the rotating abrasive throwing wheel through an abrasive supply line Z, which conducts the abrasive into the central part of the rotor where means are provided for controlling the direction of discharge of the abrasive fired from the rapidly rotating wheel. Such directional control means may comprise a tubular control cage c which extends into the central space within the rotor and which is adjustably secured to the wheel housing h. The abrasive conducted into the tubular control member c by the abrasive supply line Z is driven out through a discharge port in the tubular side wall of the control cage and into the path of rotation of the blades of the wheel by an impeller i which is suitably fixed to the wheel to rotate therewith. The abrasive throwing wheel r, tubular control cage c and impeller i may be constructed similarly to that shown in my United States Patent No. 2,162,139, issued June 13, 1939.

The wheel housing h is fixed to a framework f attached to the shell or casing of the driving motor m. 'I'his framework is supported in a sling device s from which the portable unit may be suspended or supported. A suitable manipulating handle k is attached to the framework f and is preferably spaced a safe operating distance from the abrasive throwing wheel r. Suitable push buttons or switch controls are carried by or positioned adjacent the manipulating handle lc for starting and stopping the trolled :blast red from the wheel may be directed against the desired surface area of the workpiece w by rotating the manipulating handle -k which in turn rotates the framework f in its supporting sling s so as to place the discharge outlet of the wheel housing h adjacent the desired surface area of the workpiece. This manipulation will automatically adjust the discharge opening in the control cage c which is attached to the housing h so that the directed blast from the wheel will always discharge out through the outlet in the wheel housing h, 'irre- `spective of the clockdial position into which the discharge outlet in the housing h is rotated.

The abrasive throwing wheel or rotor r may comprise a pair of spaced generally parallel extending side wall forming discs I`I and I2 which are held in spaced position by suitable spacing studs I3. A plurality of radially arranged abrasive throwing blades IIl, formed of wear resistant metal, are positioned between and supported by spaced side wall discs I I and I2, the blades I9 extending inwardly short of the axis 'of rotation of the rotor to define a central space. The side wall discs II and I2` have each a circular opening I4 in the center thereof to further 'define the circular central space within the rotor, the peripheral edges of the central openings I4 being substantially in alignment with the inner ends 'of the blades I9.

Each of the blades I comprises a relatively fiat bottom wall I5 and substantially parallel extending flanged side walls I6 which seat withimpaired grooves II provided in the side wall discs II and I2. movably secured to the side wall discs II and I2 by set screws I8 'which extend through threaded openings in the sidewall discs II and I2 and engage the adjacent side edges of the blades.

The blades can thus be removed through the periphery of the wheel when worn and new blades inserted. The rotor` 1` is fixedly secured 'to the shaft 6I of the motor m by means of `a hub I9 secured to the shaft by suitable spline 62', the hub I9 being bolted to the side wall disc "I2 as by bolts I9.

The tubular control cage c, as shown more particularly in Figs. 4, 5 and '7, formed as a onepiece casting or forging of wear resistant metal, has a tubular sidewall which extends into the central `space within the rotor 1r, A discharge port 2I is provided in the tubular side wall 20 of the control cage. The discharge port 2I isso shaped that the side edges thereof are normally positioned between the flanged side edges I6 of the blades I9. The peripheral length of the discharge port 2'I determines the spread or length of arc of abrasive discharged from the bladed rotor r, and it will be appreciated that the peripheral length of the discharge vport 2| may be made to suit operating requirements. Usually it is desired to concentrate the abrasive discharged from the rotor over a relatively limited arc and the peripheral length of the discharge Vport 2I would be accordingly reduced.

Each of the blades Ill is re- The inner end of the tubular control member c extends into a circular cavity or pocket 2 2 in the hub I9, the hub being provided with equally spaced air admission po-rtholes or passages 2'3 which communicate with the pocket 22, which serve to reduce the effect of disturbing air currents within the wheel whereby Ia more uniform 'flow `of yabrasive through the discharge port 2I is obtained.

'I'he interior surface of the tubular wall 20 of the control cage c is vprovided with a spiralling rib 24 which extends from the rear end of the control cage up to `the adjacent side edge of the discharge port 2|. The rib 24 defines a spiralling passage 25 along which any stray abrasive which has worked its way rearwardly of the discharge ports 2I may be driven forwardly by the fan action of the impeller i to place this stray abrasive into position to be discharged by the impeller i out through the discharge port 2l. The outer Aend of the tubular wall 20 of the control cage terminates in an outurned fiange 2'6 which provides va means by which the control cage can be secured to the rotor housing h. A circular flange or lip portion 28 is formed integral with the inside surface of the tubular wall y20 of the control cage which cooperates with a flange '68 associated with Vfeed line Z to provide a seal which prevents escape of abrasive from the front end of the control cage. The flange 28 is spaced forwardly of the discharge port 2l so as not to interfere with the proper operation of the impeller z'.

The impeller z', as shown in Figs. 4, 5 and 8, is positioned within the control cage c and may be made from a one-piece casting or forging of wear resistant metal. It is provided with a shank or neck portion 39 having a foot portion 39 which seats against the bottom 22 of the hub pocket 22. The impeller further comprises a circular front wall 3| and a circular rear wall 32 between which is positioned a plurality of equally spaced impeller Avanes 33 which are equal in number to the throwing blades lil of the rotor and which may extend inwardly short of the axis of rotation of the rotor to defi-ne a central abrasive admitting space 34. The circular front wall 3l of the impeller may be provided with a central opening 35 through which the abrasive -is admitted, and this front wall may also be provided with an inclined inside wall surface 35 to more effectively guide and direct the abrasive through the discharge port 2| of the control cage c. The shank portion 39 of the impeller z' may be provided with a vcircular recess 39 into which the end of the motor shaft 6I projects, the impeller being flxedly secured to the end of the motor shaft 6I by a sturdy threaded bolt 38 which extends through shank portion 39 of the impeller and screws into a threaded hole in the end of the motor shaft G-I.

Each of the impeller vanes 33, as shown in Fig. 5, should be so set that the throwing face thereof is slightly forward of the advancing face of the corresponding blade Ill of .the rotor, so that each vane will discharge its load of abrasive .uniformly onto the inner end of its corresponding blade with the least possible obstruction as the blade passes over the discharge port 2| of the control cage. To assure that the vanes s3 of the impeller z' are xedly held in the proper advance position with respect to the blades lil of the wheel, a stud 33 which extends into the foot 'portion 39 of the impeller and into a suitable aperture in the bottom wall 22 of the hub I9,

is provided. A circular cavity 31 extends around the shank portion 30 of the impeller between the rear wall 32 and the foot portion 39. The circular cavity 31 may be interrupted by one or more transversely extending ribs 31 which serve as a fan to drive stray abrasive along the spiral passage 25 of the control cage forwardly into port discharging position. The construction of the abrasive throwing rotor 1 including the apertured hub |9, the control cage c and impeller z', is described in detail in my United States Patent No, 2,162,139.

The abrasive supply line l comprises a section of exible tubing 49 whose upper end is detachably connected to an abrasive supply funnel |99 xedly suspended under the discharge spout |12 of an abrasive supply bin b. The lower end of the flexible tubing is inserted into the enlarged boss 42 of an abrasive feed spout 4|. The boss portion 42 is provided with an inturned shoulder 43 against which the inner end of the ilexible conduit 42 abuts. A set screw 44 threaded into the side wall of the boss portion 42 frictionally engages the side wall of the flexible conduit 49 to hold the same in position. The internal bore 45 of the feed spout 4| and the flexible conduit 46 presents smooth and uniform wall surfaces so that the abrasive can iow therethrough with minimum friction. The outturned flange 48 adjacent the discharge end 41 of the feed spout is arranged to abut against the outside surface of the circular rib or ange 25 of the control cage to prevent leakage of abrasive out through the front end of the control cage. The inner end 41 of the feed spout 4| may terminate just outside of or in the center opening 35 in the front wall 3| of the impeller i, so that the abrasive will be discharged into the central space 34 within the impeller and fall into the path of rotation of the impeller vanes 33. In one form of the invention, the underside of the feed spout 4| may be provided with a boss 46 which has an external cavity 49 which receives an element of a device 15 for holding the discharge end of the feed spout in proper discharging position.

As shown more particularly in Figs. l, 2, 4 and 5, the abrasive throwing rotor 1', control cage c, impeller i, a portion of the hub I9 and a portion of the feed spout 4|, are contained within a housing h comprising a body section 5t and a cover section 5|, both sections being formed of steel plate shaped to the required contour. The body section 5B comprises a front wall 52, a rear wall 53, and generally arcuate shaped side walls 54 which may be generally circular in contour but otherwise spaced from the wheel periphery. The front wall 52, rear wall 53 and side walls 54 are out off at their lower ends to define a discharge opening 55 which is of sufficient size to permit the free ejection of the directed stream of abrasive thrown by the wheel therethrough. The front wall 52 is provided with a circular shaped opening 56 through which the front end of the control cage c projects. The rear wall 53 of the body section is also provided with a circular opening 51 through which a portion of the hub I9 of the rotor T projects. The opening 51 is surrounded by a tubular collarr portion 58 which terminates in an outturned flange 5S by means of which the housing is secured to the framework f.

The cover section of the housing comprises generally a front wall portion 52 coplanar with the front wall portion 52 of the body section, a

rear wall portion 53' coplanar with the rear wall portion 53 of the body section, and a generally arcuate shaped top Wall 54 which forms in effect a curved extension of the side Walls 54 of the body section. The lower `edges of the front wall portion 52 and rear wall portion 53 and the lower edges of the curved top wall portion 54 of the cover section are so shaped and constructed that when the cover section is in closed position, a stream-lined t with the top edge of the front wall portion 52, the top edge of the rear wall portion 53 and the top edge of the side wall portions 54 of the body section, is obtained.

Suitable means are provided for locking the cover section 5| to the body section 50. Such means may comprise a pair of spaced lugs 63 projecting laterally from each of the side wall portions 54 of the body section. Each end of the top wall portion 54 of the cover section terminates in an outturned foot portion'64 which seats over the adjacent lug portions 63, as shown more particularly in Figs. 1, 2 and 5. Each foot portion 64 is provided with an open-ended slot 65. A threaded eye-bolt 66 having an eye portion 61 through which a pin 68 extends has a shank portion extending through the open slot 65 in the foot portion 64. The pin 68 extends through openings in the spaced paired lugs 63 with the eye head 61 of the bolt positioned between the paired lugs. A cap nut 69 is threaded down over the threaded shank of the eye-bolt 66. Each cap nut may be manipulated to seat against the adjacent foot portion 64 and draw the cover section 5| to the body section 5|! so that they together form an enclosed housing. It will be appreciated that the cover section 5| may be removed by loosening the cap nuts 69 suiiicien'tly to permit the eye-bolts 65 to be swung outwardly. When the cover section'5| is removed the wheel can be readily inspected and the blades' l0 removed or replaced as desired.

The device 10 for securing the discharge end of the feed spout 4| in operating position may comprise a lug1| having a foot portion 12 which t may be secured as'by threaded bolts 13 to the front wall 52 of the body section 50 of the housing in a position adjacent the opening 56 therein. An arm member 14 is swingably connected to the lug 1| by means of a threaded screw or bolt 15 which extends through aligned apertures in the lower end of the arm 14 and the lug 1| A threaded nut 16 is threaded over the shank of the bolt 15 and may be manipulated by a wing 11 formed as an integral part of the nut 15. The upper end of the arm 14 carries a cylindrical portion 18 within which is screwed a threaded stud 19 having a cone-shaped end 19 which seats within the cone-shaped cavity 49 provided in the boss 46 of thev feed spout 4|. By manipulating the wing 11 of nut 16, the nut can be loosened so as to permit downward swinging movement of the arm 14 so as to permit the inner end of the feed spout 4| to be withdrawn from the tubular control cage c. 'Ihe control cage c and the impeller i can then be readily assembled, adjusted, repaired or replaced. When abrasive flow connection is to be made, the discharge end 41 of the feed spout 4| is inserted into the control cage until the laterally extending flange 48 thereon seats against the inwardly extending rib 28 on the control cage. The arm 14 is then swung upwardly, the cone-shaped end 19 thereof pressed into seating engagement with the cone-shaped cavity 49 in the boss 46 of the feed spout 4|, and the nut 16 then manipulated by turning the wing so as to frictionally secure the. arm 1.4 in oper-- ating position.

To protect the enclosing walls 52, 53 and 54. of the body section 50 and walls 52', 53' and 54 of the cover section 5I of the housing h, from damage due to possible stray blast, these walls are suitably lined on their inner surfaces. with wear resistant metal plates 8| which are shaped to the contour of the surface which they are to cover and are secured in position as by suitable metal screws 82. The abrasive throwing rotor r equipped with a control cage c and impeller i of the type herein illustrated and described, results in a minimum of misdirected stray abrasive.

The supporting framework f comprises a pair of heavy spaced metal disc-shaped plates. 85 and- 86, between which the wheel driving motor m is. positioned. The front disc-shaped plate 85 is provided with a central aperture 80 through which the bearing portion 8l of vthe motor may extend. The disc-shaped plate 85 may likewise be provided with a central opening 08 throughwhich the bearing portion 89 of the front end of the motor may extend. Bearing portions 81 and" 89 rotatably support the motor shaft 6|. The

motor m has not been illustrated in detail since any well known make of motor known to the art may be used. Either a constant or variable-speed motor may be selected, but preferably a constant speed motor is employed. The frame disc 86l may be suitably bolted to the motor casing 90 by a plurality of spaced threaded bolts 9| whose ends are threaded into the motor casing 90. Each bolt 9| may extend through a tubular collar 921,

which collars maintain the proper spaced rela-- tionshop between the supporting disc 80 andl motor casing 90. The supporting disc 85 may likewise be secured to the motor casing 90 by'spacedV bolts 93, the disc S5 being maintained in proper spaced relationship from the motor casing 90- by tubular collars 9A which surround a portion of the bolt shank.

The rear wall 53 of the wheel housing merges into a contracted tubular neck portion 58 which provides a housing for a portion ofthe wheel hub |9 and motor shaft 5|. The wheel housing h may be secured to the frame f by the bolts 93 which extend through openings in an outturned flange portion 59 extending from the end of the tubular neck portion 58. The outturned flange portion 59 seats against a circular spacer plate 95 having holes through which the bolts 9'3v extend, the spacer plate 95 beingv spaced from the; frame disc 35 by tubular collars' 96 through which the bolts 03 extend. Spacer plate 95 may beprovided with an opening 91 through which the front bearing 81 of the motor extends. The spacer plate 95 and collars 96, could, of course, be done away with by lengthening the tubular neck portion 50 of the housing so that the flange portion 59 thereof would seat against the outside face of the supporting disc 85. It is important that the housing h be rigidly but removably secured to the framework f without in any way interfering with the free rotation of the rotor 1.' and motor shaft 6|, but it is appreciated thatv numerous different types of securing arrangements may be provided within the purview of this invention.

The unit may be supported in. a suitable sling s which comprises a pair of straps of sturdy construction which are generally circular in form and each provided with a track |01.. *Each of the supporting discs 85 and 86 is provided witha peripheral groove |02 each of which defines a pair of spaced peripheral flanges |03. A series of spaced rollers |04 each rotatably mounted on a pin |05 are arranged to roll over the nor mally stationary circular track |0|. Each pin |05 projects 'through the anges |03 of the supporting disc so as to permit free rotative movement of the rollers |04 thereon. The spaced' flanges |103 are designed to overlap the adjacent sides of the track |0-| to maintain the rollers |104 on the track |0|.

For convenience in assembly', each of the circular shaped straps |00 may be formed in two half sections, as shown i-n Fig. 6. Each half section is provided with a foot portion |05` extending laterally from each end thereof. Between adjacent pairedl foot portions |06 at one side of the motor a lift bar |0T extends which is secured to the foot portions |05 by a suitable threaded bolt or screw |08 which also holds the adjacent ends of the sections in abutting track formation. A stiffening bar |01 may bepositionedbetween the foot portions |06 opposite the lift bar |01` andV may be connected to adjacent foot portions |05 by a similar securing screw |08. It will be appreciatedA that when'the two half sections of each circular strap are connected as by screws |08; a generally circular track |03| upon which the rollers |04 may roll isprovided. The lift bar |0|l may be provided with a pluralityv of spacedl holes |09 into which the hooked' ends |-I of the metal lifting loop H0' may be inserted into any selected pair of openings |09 which are nearest the center of gravity of' the unit when in operation. Y

The unit may be suspended from the l-ift loop H05l by any suitable lift device t. There is shown in Fig. l a block andi tackle arrangement which may be used for this purpose, which comprises a lower pulley ||5 which is connected to an upper pulley |16 by a chain The upper pulley is'. provided with the usual clevis |8 having a swivel hook ||9 hooked into an eye-bolt |20secured toa fixedor movable frame support |2|. The upper pulley H6 is provided with a convenient locking dog |22 which holds the chain xed in any desired position. The lowerpulley ||5 carries a clevis |224y provided with a swiveledl hook |23 which hooks. into. the lifting loop H0'. Thus with such a block and tackle arrange-v ment the blasting unit. may be' raised and lowered.

or swung into various angular positions limited only by the length of the blocki and tackle suspension t. It is appreciated. that otherunit. supporting means operably connected to. the unitv may comprise a handA wheel |25 providedv with.

the usual rim |26A connected to a collar |2`|` by spokes |28; Thepcollar |2-'| is connectedto a hollow tubing |29 asl by set screws |30. Thev tubing |29` is provided with an outwardly flared flangev |3| whichY may be bolted as by the bolts 9|; to the supporting disc 8.6 of the framework f.

TheV tubing |29v may be of any desired length, from a few inches to several feet, and provides a means for rmly connecting the handv Wheel |25 to the rotatably mounted supporting discA at any ldesiredA convenient distance fromV the abra sive throwing Wheel 1'.

The tubing |29 provides a convenient housingv for a switch box |32 positioned within the end thereohaving a cover panel |33 removably secured to the switch box as by screws |34. The switch box and cover panel may be made of suitable insulating material, such as hard rubber or phenolic resin. The cover panel |33, as shown in Figs. 3, 4 and 9, has a push button |35 for throwing the motor out of operation and a push button |35 for throwing the motor into operation, these buttons being operably connected to a suitable snap switch |31 contained within switch box |32. .This switch may be of any standard make, such as that illustrated in the drawings, comprising a rocker plate |38 pivotally mounted upon a shaft` |39 which extends through an insulated boss |40 provided on the interior of the cover panel |33. Rocker elements |4| fixed to the ends of the shaft A|39 are each provided with a foot portion |42 having a projecting pin |43 surrounded by a spring coil |44. The upper end of each pin |43 extends through a hole in a bracket element |45 attached to the rocker plate |38. The rocker plate |33 is provided with a tongue projection |45 extending from each end thereof, which extends loosely through an elongated slot |47 in a leg |43 attached to each of the push buttons |35 and |35. The lower end of each leg |48 is adapted to reciprocate in a slot or recess |49 provided in the bottom wall of the switch box |32.

Thus, when the start push button 36 is pushed in, the switch plate |38 is rocked about the shaft |39 so that the laterally extending brackets |45 connected to the rocker plate |38 swing the pins |43 to a point where the coil springs |44 further f swing the foot portions |42 into electrical contact with the switch contact element |55. The power line |5| carrying the Contact prongs |52 plug into the contact receivers |53 and |54. Contact receiver |53 is electrically connected to one of the lead wires |55 leading to the motor. Contact receiver |54 is electrically connected to the other motor lead wire |55, so that when the 'foot portions |42 of the snap switch are in electrical contact with the contact element the circuit to the motor is closed and the motor thrown into operation. When switch button |35 is pressed, the switch plate |38 is pivoted so as to swing the foot portions |42 out of electrical contact with contact element |50 so as to open the motor circuit and halt the motor. It will be appreciated that other forms of standard switches may also be used for the purpose.

It will be noted that the power line |5| carrying the contact terminals |52 is positioned substantially concentric of the axis of rotation ofthe motor so that the discharge opening 55 of the rotor housing can be swung into substantially any clockdial position without interference from the power line. It will also be noted that the switch box |32 containing the snap switch and the motor wiring is all positioned within the tubular member |29 and thus completely housed and protected from damage. It will be appreciated that a generally circular metal shield 205 may be attached to or supported by the circular hangers |00 as by screws 255 to further protect the motor and parts of the machine against possible injury due to flying abrasive. As shown in Figs. l and 4, the housing 200 (partially broken away in Fig. l) may be formed in two half sections, one half section extending between lift bar |01 and the stiiening bar |02 on one side of the motor, and the other half section extending between lift bar |07 and stiiening bar |01" on the other side of the motor. Each half section may be provided with an inturned half circular iiange 20| at each side thereof, each flange having a clamp formation 202 thereon within which a felt or rubber sealing gasket 203 may seat. The

housing flange 20| positioned adjacent the wheel housing h is arranged so that its gasket 203 will bear against the outer periphery 204 of the spacer plate 95. At the opposite end of the motor the frame plate 86 may be provided with a circular boss 255 against which the adjacent sealing gasket 203 may seat. `Thus all working parts of the machine may be completely enclosed and protected.

A xed relationship should be maintained between the clockdial position of the discharge port 2| in the control cage c and the discharge opening 55 in the housing h, so that the control cage will properly direct the conned stream of abrasive out through the discharge opening 55 and not against the housing walls. The proper clockdial position of the discharge port 2| in the control cage to effect this result in a wheel of given blade length and rotated at a given speed,

canv be quickly determined by observation and from experience. Generally speaking, the abrasive throwing wheel having a comparative blade length with respect to the wheel diameter, as illustrated in Figs. 4 and 5, should have its discharge port at approximately between the one and two oclock positions when the center of the discharge opening 55 in the housing is located at approximately the six oclock position, considering the whee1 as rotating clockwise.

For convenience in adjustment, the outturned iiange 26 of the control cage is provided with a marker |50 which indicates the position o the discharge port 2| in the control cage. The outturned iiange overhangs a circular rim |6| adjustably xed to the front wall 52 of the wheel housing h by leveling screws |55. A plurality of cooperating clamp elements |62 overlie the rim member |6| and are in position to clamp the outturned flange 26 of the control cage thereto when the screw bolts |63, one of which extends through a suitable screw opening in each clamp member |62 and into a threaded opening in the rim member |6| are tightened. If clockdial adjustment of the discharge port 2| in the control cage is desirable, the set screws |63 may be loosened and the control cage c rotated either clockwise or counterclockwise so as to bring the discharge ports 2| thereof in the desired clockdial position as indicated by the marker |60 thereon. The outer surface of the rim. member |5| may be provided with indicating numerals |64, such as appear on the face of a clock, so that the proper setting for the control cage discharge port 2| may be observed and noted. lt will be appreciated that the rim member 45| should provide a smooth machined seating surn face IGI for the outturned flange 25 of the control cage and that this rim should be leveled so that the longitudinal axis of the control cage is fin proper alignment with the axis of rotation of the wheel. This may be easily eiected by manipulating the leveling screws |55 which secure the rim member |6| to thefront Wall 52 of the housing. The foot portion 12, as shown in Fig. 2, may be formed as an integral part of the rim member IBI. When the rim member |6| is leveled, proper leveling adjustment of the screws 'I3 is also made.

The abrasive storage bin b may be suitably suspended from some point convenient to the opaecasar erator o.. The abrasive bin is provided with 'a hopper bottom |1| which leads into. a suitable spout |12 which may be closed and opened by a suitable pivoted valve |13. The valve |113 is provided with a suitable. semi-circular closure wall |14 closely adjacent the openend of the spout |12. A pair of spaced wings. |15 extend upwardly from the circular closure portion |154, which are secured to pins |16 pivotally mounted on the feed spout. .|12. Suitable mechanism is provided for swinging the valve |13 into closed or open position or partially closed or open position, which can be conveniently manipulated by the operator so as toy control the flow of abrasive into the flexible feed conduit 40. Such mechanism may comprise a manipulating rod |11 having a convenient handle |18V located adjacent the operator o. The rod |11 is connected to one arm of a bell crank |19 pivotally mounted on a suitable bracket |80 xed to the bottom |1| of the abrasive bin b. The other arm of the bell crank |19 is connected to one end of a rod |8| whose other end is connected to a lever |82 fixed to one of the pins |16. Friction means are provided for maintaining the spout valve |13 in any desired adjusted position, which may comprise a brake drum |83 fixed to the pin |16 enclosed within a brake strap |84 fixed as by screw |285 to the bottom wall |1| of the bin. A wing bolt |85 connecting the ends of the brake strap |84 to regulate the friction exerted on the brake drum |83 and consequently the push or pull to be exerted on rod |11 to move the valve |13, is provided. Thus by an upward or downward pull exerted on the control rod |11, the feed valve |13V can be swung into any desired open or closed position to permit the desired quantity of abrasive to be discharged from the feedI spout |12.

The abrasive discharging from the feed spout |12 falls into a receiving funnel |90 which is removabl-y connected to the upper end of the flexible feed conduit 40. The funnel |90 is suspended as by strap supports |9| fixed to the bottom |1| of the supply bin b. Thev flexible feed conduit 40 may be detachably connected to the spout porfton |94 of the funnel |90 by means of a threaded collar |95 which threads onto a threaded ring |96 fixed to the outer periphery of the spout portion |94'. A collar |91 xed to the upper end of the flexible feed conduit 40 is provided with a circular rib |98 under which an inturned lip |99 provided on the collar |95 seats. By manipulating the collar |95 the flexible feed conduit 40 may be attached to or detached from the spout portion |94 of the supply funnel |90.

The portable centrifugal blasting unit above described is admirably designed for use in what is known as a blast cleaning room. The operator o may station himself, if this is desirable, within the room, suitably protected against rebounding abrasive by a protective jacket o', a visor or helmet o and gloves 0". If it is unnecessary or undesirable for the operator to enter the cabinet, he may be conveniently positioned outside the cabinet with the manipulating handle extending through an opening in the wall of the cabinet which is otherwise closed by flexible curtains. The operator then watches the blasting operation through a suitable window provided in the wall of the blast cleaning room. Such blast cleaning rooms are old and well known in the art and need not be described in detail. It is also appreciated that the portable unit herein described need not be operated from within or Without a blastingk roorn,`

but maybe operatedin the open with only such protective shieldsas may be necessary to partially enclose the work .to prevent injury or damage to adjacent .persons or objects from Vrebounding abrasive.

Beforaoperating the unit,v any necessary acljustment-vof :the clockdial position of the discharge port 2 l. in the control cage with reference to theA discharge opening 55 in the wheel housing is first made. Once the `proper clockdial position of the control cage discharge port 2|, has been determined, no further adjustment thereof need .generally be made. The operator pushes the starting button .|361 which throws the motor my into operation which rotates the abrasive throwing; rotor ,r and its. impeller i. When the rotor has .been brought up to speed, the operator pulls; the. abrasive controlrod |115, Opening the valve |13 the. desired amount. to permit the abrasiveto flow from the storage bin b into the funnel .|99 through the conduit 40 and into the rotating impeller i. by which it is thrown out through the ydischarge port 2| into the path of rotation `of the. blades I0 of the rotor r. The blades |01 vof. the rotor fires the abrasive at blasting velocity out through the discharge opening 55 in the wheel housing h in a generally fanshaped stream of limited arcuate length. The operator swings the discharge opening 55 0f the rotor housing, into position adjacent the surfaces of the workpieces w to be cleaned and treated., Since the unit is suspended and can be swung bodily into various positions, the dischargefopening; 55 in the wheel housing can be brought progressively over the surface areas of the workpieces w to properly blast the same.

The; operator Vo observes the degree of blast cleaning as he moves the discharge opening 55 of the housing over the' surface areas of the workpieces. By turning the manipulating handle |25, the discharge opening 55 in the housing may be swung into substantially any clockdial position so. that blasting is directed at any desired angle. It is-'important to note that the discharge port 2| in 'the control cage always maintains its proper relative position with respect to the disallarga-opening 55l in the housing lh irrespective of the angular; position into which the discharge opening 5,5 of the housing is swung. Very little effort is required to swing thel discharge opening' 5.5 into any` desired blasting position since the supporting discs and 8-6 to which the motor m, handle |25 and housing h are rigidly attached, are rotatably supported on the rollers |04 which rol-l around the circular tracks |0| of. the stationary supporting straps |00. The rotor r and its impelleri are, of course, directly fixed to and supported by the shaft 0| of the motor Since both the power cable |5| and the abrasive supply conduit 40 are flexible, the driving motor m and housing h may be rotated within the circular supporting tracks |01 and may also be swung over a relatively wide area without interference. It will be noted that the Contact' point 19 of arm10 is in alignment with the axisof the rotor-r and motor m so that the arm- 1|)` can' pivot thereabout as the housing h is rotated.V -vThus the feed spout 4| remains in the downwardly inclined feeding position shown in Fig. 4 even though the housing h is rotated 360 or more, in which event the spout flange 48 merely slides on the rib 28 of the control cage. By referring particularly to Fig. 2, the housing h may be swung counterclockwise or to the left to movethe housing opening from approximately the six oclock position to approximately the one oclock position when the arm 14 will contact the downwardly inclined feed spout 4l. The housing opening 55 may be further swung to the twelve oclock position without disturbing the abrasive flow through feed spout 4|, since the outer end portion of the feed pipe may be pushed over to approximately the eleven oclock position without disturbing the downward ow of abrasive therethrough. The discharge opening 55 of the housing may be swung from the above described twelve oclock position in a clockwise direction to the twelve oclock position, in which event the arm 'I4 will push the feed spout 4l slightly to the left, as shown in Fig. 2, without interrupting the downward flow through the feed spout 4l which always remains in downwardly inclined position. It will be appreciated that proper sliding movement of the feed spout ange 48 on the control cage lip 28 is in no way disturbed when the spout 4| is swung slightly to the right or left, since the conical point 'I9' on which it pivots is directly in line with the axis of rotation of the housing h and the axis of rotation of the wheel r, as well as the longitudinal axis of the control cage c.

As a modification, a ring member 2H] may be secured to the inside face of the control cage c to retain the feed spout 4l in feeding position, as shown in Fig. '7, and yet permit 360 rotation of the control cage c and housing h thereabout. The ring member 2li] may be angle-shaped in cross-section with one leg 2II thereof secured to the tubular wall of the control cage c as by bolts 2l2. The other leg 2|3 provides a sliding abutment for the outturned fiange 48 of the feed spout, so that the spout flange 48 is free to slide between the rib 28 and the leg 23. The upward pull exerted by the conduit 40 on the spout 4I is sufficient to maintain the spout 4I in downwardly inclined discharging position irrespective of the position to which the housing opening 55 is rotated. The area over which the unit may be swung is obviously limited only by the length and character of the suspension'device t employed. If desired, the normally stationary straps may be supported upon a table or standard either stationary or movable. The centrifugal blasting unit lends itself to numerous different types and kinds of movable supports which are determined by the character of the workpieces and the position of the workpieces to be blasted.

The abrasive throwing rotor r may be made in almost any desired size, running from six inches in diameter to twenty inches or more in diameter. Abrasive throwing rotors constructed in accordance with this invention have been successfully used which are only eight inches or less in diameter with abrasive throwing blades l0 approximately only two or three inches long and three-quarters of an inch wide. Approximately only a one-horsepower motor is required to drive such a wheel, which will throw from twenty to thirty pounds of abrasive per minute. Almost any desired quantity of abrasive can be thrown by providing a wheel of sufficient diameter with blades of suicient width. Such wheels may be built to throw as small a quantity as ten pounds of abrasive per minute or less up to 2000 pounds of abrasive or more per minute. Y

Abrasive throwing wheels associated with a portable unit of the type herein described, are admirably adapted for blast cleaning operations where high pressure air blast has been heretofore used and considered the only feasible method of cleaning large, awkward or cumbersome castings and forgings, With this portable unit surface areas of castings which have only been partially cleaned by other methods can be touched up and finished, which has heretofore been done only by hand manipulated air blast nozzles. The irregular cavities in cylinder blocks and interior surfaces of steel barrels, and numerous other objects can be effectively, uniformly and economically blast cleaned and treated by the portable centrifugal blasting unit herein described, at a fraction of the cost of similar cleaning operations employing either hand or mechanically manipulated air blast nozzles. For example, a small eight inch disc wheel driven by only one horsepower motor will easily fire thirty pounds of abrasive per minute, whereas an air blast nozzle throwing a like quantity would consume compressed air which would require from fteen' to twenty horsepower to develop. This portable centrifugal blasting unit supplies the flexibility of operation which only an air blast gun has heretofore provided, at substantially reduced operating cost.

While certain novel features of the invention have been disclosed and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A portable centrifugal blasting unit including in combination, a driving motor having a normally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing wheel nxedly mounted on said projecting drive shaft, a guard housing for said wheel xedly connected to said motor casing and having an abrasive discharge opening, abrasive control means xed to said housing for directing the abrasive fired from said wheel through said opening, means for supplying abrasive to said control means including a fiexible conduit terminating in a downwardly inclined spout portion, and means associated with said spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control means whereby said housing may be rotated about an axis in alignment with the discharge end of said spout portion, means for rotatably supporting said motor and housing, and means xedly connected to said motor casing for manipulating the discharge opening in said housing into various clockdial positions.

2. A portable centrifugal blasting unit including in combination, a driving motor having a normally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing wheel ixedly mounted on said projecting drive shaft2 a guard housing for said wheel xedly connected to said motor casing and having an abrasive discharge opening, abrasive control means fixed to said housing for directing the abrasive fired from said wheel through said opening, means for supplying abrasive to said control means including an abrasive supply bin, a iiexible conduit connected to said bin and terminating in a downwardly inclined spout portion, and means associated with said spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control means whereby said housing may be rotated about an axis in align-'ment with the discharge end of said spout portion, means for rotatably supporting said motor and housing, and means iixedly connected toy Said motor casing for manipulating the discharge opening in said housing into various clockdial positions. V

3. A portable centrifugal blasting unit including in combination, a driving motor having a normally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing wheel xedly mounted on said projecting drive shaft, said wheel having a plurality of radially arranged blades extending inwardly short of the axis of rotation of said wheel to provide a central space, a guard housing for said wheel fixedly connected to said motor casing and having an abrasive discharge opening, a tubular abrasive control member extending into said space and fixed to said housing for directing the abrasive fired from said wheel through said opening, means for supplying abrasive to said control member including a flexible conduit terminating in a downwardly inclined spout portion, .and means associated with said spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control member whereby said housing may be rotated about an axis in alignment with the discharge end of said spout portion, means for rotatably supporting said motor and housing, and means flxedly connected -to said motor casing for manipulating the disnormally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing wheel iixedly mounted on said projecting drive shaft, said wheel having a'plurality of radially arranged blades extending inwardly short of the axis of rotation of said wheel to provide a central space, a tubular control member extending into said central space having an abrasive discharge port in the tubular side wall thereof, an impeller positioned within said tubular control member fixed to rotate with said blades and operable to project abrasive through the discharge port in said control member and into the path of rotation o f sai-d blades, a guard housing for said wheel `rlxedly connected to said motor casing and having an abrasive discharge opening, means for adjustably securing said control member to said housing whereby the abrasive fired from said wheel is directed through said opening, means for supplying abrasive to said control member including a exiblecond'uit terminating in a downwardly inclined spout vportion, and means associated withsaid spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control member whereby said housing may be rotated about an axis in alignment with the discharge end of Asaid spout portion, means for rotatably supporting said motor and housing, and means xedly connected to said motor casing for manipulating the discharge opening in said housing into various clockdial positions. v

5. A portable centrifugal blasting unit rincluding incombination, a driving motor having a normally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing `and means associated with said spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control means Where- Joy 4said housing may be rotated about an axis in alignment with lthe discharge end of said spout portion, a suspension device for rotatably supporting 4said motor and housing, and means for manipulating the discharge opening in said housing into various clockdial positions, said manipulating means being xedly connected to said motor casing at a point removed from said shaft and out of the path of rebounding abrasive.

6..A portable .blasting unit including in combination, a driving .motor having a normally stationary enclosing casing and a projecting rotatable drive shaft, an abrasive throwing wheel iixedly mounted on .said projecting drive shaft, a guard housing for said wheel having a brasive discharge opening, a framework fixed to sai-d `motor casing and to said guard housing, abrasive control means fixed to said .housing operable to direct abrasive yfired from said wheel through said openingVmeans for supplying abrasive to 4said control means including a flexible conduit terminating inv a downwardly inclined spout portion,` and means associated with said spout portion and said housing lfor movably retaining said Aspout portion in downwardly inclined `feeding relationship with respect to said control .means whereby said housing may be rotated about an axis in alignment with the discharge end of said lspout portion, a movable suspension device, `'means connected to said suspension device for rotatably supporting said framework, and means connected to said framework for manipulating said motor and housing so as to position the discharge opening in said vhousing in various clockdial positions. v

7. A portable blasting unit including in combination, a driving motor having a projecting rotatable drive shaft, an abrasive throwing wheel xedly mounted on said projecting drive shaft, a guard housing for said wheel having an abrasive discharge opening, a framework-for supporting said motor and housing, means for flxedly connecting said housing to said framework, abrasive control means fixed to said housing'operable rto direct abrasive fired from vsaid wheel about an axis in alignment with the discharge end of said spoutportion, spaced generally circular track members upon which said framework is rotatably supported, movable means for supporting said track members, and means connected to said. framework for manipulating said motor and housing so as to position the discharge opening in said housing in Various clockdial positions.

8. A portable blasting unit including in combination, a driving motor having an enclosing casing and a projecting rotatable drive shaft, an

abrasive throwing wheel xedly mounted on said projecting drive shaft, a guard housing for said wheel having an abrasive discharge opening, spaced circular discs secured to said motor casing, means for securing said housing to said discs, abrasive control means xed to said housing operable to direct abrasive fired from said wheel through said opening, a flexible conduit for supplying abrasive to said control means, a circular track member rotatably supporting each of said discs, la movable suspension device connected to said track members, and means connected to one of said discs for manipulating said motor casing and housing so as to position the discharge opening in said housing in various clockdial positions.

9. A portable blasting unit including in combination, a driving motor having a projecting rotatable drive shaft, an abrasive throwing wheel flxedly mounted on said projecting drive shaft, a

guard housing for said wheel having an abrasive ,r

tion and housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control means whereby said housing may be rotated about an axis in alignment with the discharge end of said spout portion, a movable suspension device, means connected to said suspension device for rotatably supporting said framework, a hand wheel connected to said framework nearest the end of said motol` most removed from said wheel for manipulating the unit so as to position the discharge opening in said housing in various clockdial positions, and electrical control means positioned adjacent said hand wheel for controlling the operation of said motor.

,10, A portable blasting unit including in cornbination, a driving motor having a projecting rotatable drive shaft, an abrasive throwing wheel xedly mounted on said projecting drive shaft, a guard housing for said wheel having an abrasive discharge opening, a framework for Supporting said motor and housing,means for fixedly connecting said housing to said framework, abrasive control means fixed to said housing operable to direct abrasive fired from said wheel through said opening, a flexible conduit for supplying abrasive to said control means, a movable suspension device, kmeans connected to said suspension device for rotatably supporting said framework, a tubular member connected to said framework, a hand wheel xed to said tubular member for manipulating the unit so as to position the discharge opening in said housing in various clockdial positions, and electrical control means positioned centrally of said hand wheel and housed within said tubular member for controlling the operation of said motor.

ll. A portable centrifugal blasting unit including in combination, a driving motor having a normally stationary casing and a projecting-rotatable -drive shaft, an abrasive throwing wheel iixedly mounted on said projecting drive shaft, said wheel including a rotor head having a plurality of generally radially arranged abrasive throwing blades extending inwardly short of the axis of rotation of said rotor head to provide a central space, a guard housing for said wheel having an abrasive discharge opening flxedly connected to said motor casing, a tubular control member extending into said central space having an abrasive discharge outlet in the tubular side wall thereof for directing abrasive onto the inner ends of said blades at a predetermined clockdial position, an impeller positioned within said tubular control member and fixed to rotate with said blades for projecting the abrasive through the discharge outlet in said control member, means for adjustably securing said control member to said housing for `directing the abrasive red from said wheel through said opening, means for supplying abrasive to said tubular control member, means for rotatably supporting said unit, and means connected to said motor casing for manipulating the discharge opening in said housing into various clockdial positions, said abrasive supply means including a flexible conduit terminating in a downwardly inclined spout portion, means providing an abrasive seal between said spout portion and said tubular control member, and means movably securing said spout portion to said housing whereby said housing and said control member may be rotated about an axis in alignment with the discharge end of said spout portion.

12. A portable centrifugal blasting unit including in combination, a driving motor having a normally stationary casing and a projecting rotatable drive shaft, an'abrasive throwing wheel connected to said projecting drive shaft, a guard housing for said wheel having an abrasive discharge opening xe'dly connected to said motor casing, abrasive control means fixed to said housing' for directing the abrasive fired from said wheel through said opening, an abrasive supply bin a flexible conduit terminating in'a downwardly inclined spout portion for conducting Vabrasive from said bin to said control means, means for rotatably supporting said unit, means providing an abrasive seal between said spout portion' and said control means, means lxedly connected to said motor casing for manipulating the discharge opening in said housing into vvarious clockdial positions, and means providing a swivel connection between said spout portion and said control means whereby said spout portion is maintained in downwardly inclined feeding position when said housing is rotated about said spout portion.

13. A portable centrifugal blasting unit including in combination, a driving motor 'having a normally stationary outer casing and a projecting rotatable drive shaft, an abrasive throwing wheel fixedly mounted on said projecting drive shaft, said wheel having a plurality of radially arranged blades extending inwardly short of the axis of rotation of said wheel to provide a central space, a guard housing for said Wheel fixedly connected to said motor casing'and having an abrasive discharge opening, a tubular abrasive control member extending into said space andv fixed to said housing for directing the abrasive red from said wheel through said opening, means for supplyabrasive to said control member including a iiexible conduit terminating in a downwardly inclined spout portion, and means associated with said spout portion and said housing for movably retaining said spout portion in downwardly inclined feeding relationship with respect to said control member whereby said housing may be rotated about an axis in alignment with the discharge end of said spout portion, means for rotatably supporting said motor and housing, and means iiXedly connected to said motor casing nearest that end of said motor which is opposite to the end mounting said Wheel for manipulating the discharge opening in said housing into various clookdial positions.

14. A portable blasting unit including in combination, a driving motor having an enclosing casing and a projecting rotatable drive shaft, an abrasive throwing Wheel xedly mounted on said vtracks enclosing said tracks, motor and motor casing, a movable suspension device connected to said track members, and means connected to one of said discs for manipulating said motor casing and housing so as to position the discharge opening in said housing in various clockdial positions.

CHESTER E. UNGER. 

